Phonograph



W. F. LUHNOW.

PHONOGRAPH.

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IIIIIIIIIIIIIIIII AN.5, 1920. Patented Nov. 21, 1922.

Patented Nov. 21, 1922.

UNITED STATES WALTER F. LUHNOW, OF OAK PARK, ILLINOIS.

IHONOGRAPH.

Application filed January 5, 1920. Serial No. 349,444.

1 0 all 10 from it may concern:

Be it known that I, lViiL'rni-i F. LUHNow, a citizen of the United States of America, and a resident of Oak Park, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Phonographs, of which the following is a specification.

This invention relates mainly to phonographs, and more particularly to the horn or amplifying means therefor. I have investigated this subject and have conducted experiments whereby I have found that in a phonograph horn or similar amplifying chamber there is in some degree a pumping action tending to urge the air in the direction of the sound, and that provision for ad mitting air at the small end of the born or amplifier tends to equalize the pressure and improve the sound efficiency of the instrument.

The main objects of the invention are to prwide sound amplifying means and attachments therefor of improved form adapted for more eflicient reproduction of sound and particularly adapted to reproduce more acein'ately a wide range of tones, and with greater accuracy as to timbre and sensitiveness to sounds of extremely small volume or intensity.

Illustrative embodiments of this invention are shown in the accompanying drawings, in which Fig. 1 is a plan of an amplifying horn of U-shape with the reproducing attachment seto the middle part thereof.

Fig. 2 is a central vertical section through the reproducer and adjacent part of the amplifying horn at 22 on Fig. 1.

Fig. 3 is a plan of a reproducer having attached thereto a pair of complementary amplifying members, one of which is hornshaped for omitting the sound, and the other of which is relatively small and nearly tubular in shape for equalizing the pressure back of the diaphragm.

Fig. 1 is a plan of another embodiment in which the main amplifying horn is provided with an upward equalizing arm.

Fig. 5 is a fragmentary section at 5-5 on F ig. 4.

In the construction shown in Figs. 1 and 2, the U-shaped amplifying horn 1 is disposed horizontally over the disk record 2 1n movable relation thereto to accommodate the progress of the needle from the outer part of the record toward the center, as understood in the art. For this purpose the horn is pivotally supported on an upright rod 3 having a cross-arm 4i whereon the branches 5 and 6 of the horn rest, and a spacing rod 7 extending from the cross arm to the middle part of the horn where it is secured as at 8. The ends of support 4 are turned upward to hold the horn in place. In this instance a hill and dale type of reproducer 9 may be attached to the horn, preferably adjacent to the middle of the convex side of the bend.

In the modified construction shown in F 3 the reproducing and amplifying means are mounted in similar relation to the record disk 2, but with the essential difference that the reproducer 10, instead of being attached to the middle part of a continuous integral horn is secured to the adjacent ends of a pair of complementary horn members 11 and 12, one of which serves as a reproducer proper, and the other merely as an equalizing mem her. The said members 11 and 12 are set rigidly in the back of reproducer 10 and both communicate with the chamber thereof. The amplifier device is suported to swing horizontally on the vertical pivot 13. The members 11 and 12 rest on the cross-arm 14- and are secured by a centrally apertured pivot plate 15.

In the embodiment of Figs. 4 and 5 a zigzag type of reproducer 16 is attached to the side of an amplifying horn 17 near its small end, which is closed. Said horn is provided with an equalizing branch 18 communicating therewith adjacent to the reproducer. Said branch 18 may well be disposed over the horn 17, though such relation is not essential. A pivot plate 19 is secured to the horn 17 near its large end for supporting it turnably on the vertical pivot 20. The reproducer 16 operates on a corresponding record plate 21. The outer end of branch 18 is open to admit air, substantially as in each of the other embodiments.

Although but a few specific embodiments of this invention are herein shown and described, it is to be understood that some of the details of the constructions shown may be altered or omitted without departing from the spirit of this invention as defined by the folowing claims.

I claim:

1. A device of the character described, in

the form of an amplifying horn open both at the large end and at the small end and provided with a phonographie sound reproducer attached thereto at a medial point thelreof, said horn being flared from end to enc.

2. A device of the character described, in the form of an amplifying horn open at both ends and provided with a phonographic 10 sound reproducer attached thereto at a medial point thereof, said horn being flared from end to end and being U-shapech the reproducer being located adjacent to the middle of the bend and said horn being convergent in one direction from said reproducer and divergent in the other direction.

Signed at Chicago this 22d day of December 1919.

WALTER F. LUHNOW. 

